Load bearing member

ABSTRACT

A load bearing member comprising: a first rigid portion ( 12 ) adapted to bear a load until the load reaches a predetermined load and thereafter have a reduced or substantially no load bearing capacity; and a second flexible portion ( 14 ) adapted to bear the load after the predetermined load is reached, wherein the first rigid portion and the second flexible portion cooperate to bear the load such that the load bearing member is enabled to transform from rigidly to flexibly bearing the load when the predetermined load is reached.

The present invention relates to normally rigid members including:structural components such as beams, columns and the like; andconnecting components such as mechanical fasteners. In particular, butnot exclusively, the invention relates to apparatus having an improvedperformance during dynamic loading, such as destructive vibrations andmovements created during earthquakes; and a method of limiting damage toboth the integrity of a structure and its non-structural elements due torelative displacement or acceleration forces or dynamic loading.

During construction of any structure within the built environment, forfacilities such as buildings, bridges, platforms and the like, it iscommon to rigidly connect structural components using compressionfixings or welding. However, seismic wave propagation (expressed asRayleigh, Love, Primary or Secondary waves) and the associated movementsof an earthquake or explosion can cause severe shock waves and intensevibrations which affect base structural components at the foundation ofthe structure and, in turn, can adversely affect any other structuralcomponents which are directly or indirectly rigidly connected to thebase components. These types of disturbance can cause damage to, or eventhe collapse of, the structure.

Also, non-structural components of buildings, such as electrical plant,HVAC equipment, windows, ceilings, and external cladding are typicallyrigidly connected to the building. These non-structural componentstypically represent around seventy percent of a building value, and thecontents of the building can be many times the value of the building.Damage to these non-structural components in an earthquake can result inenormous financial loss, significant business interruption and loss ofessential post earthquake services as well as, directly or indirectly,risk to life and injury. Damage surveys of earthquakes have shown that,in many cases, buildings which have only suffered minor structuraldamage have been rendered uninhabitable and hazardous to life owing tothe failure of mechanical and electrical systems and damage to thearchitectural elements. For all these reasons, the preservation ofnon-structural components may be equal in importance to maintaining theintegrity of the building structure.

Non-structural elements such as cladding may be damaged during anearthquake due to two distinct mechanisms, namely, relative displacementor acceleration. In particular, it is common for facade elements of thestructure to be distorted and shaken free from the exterior surface ofthe structure. This can be, directly or indirectly, a hazard or risk tolife.

It is therefore desirable to structurally isolate non-structuralcomponents of buildings to prevent or reduce damage, such as caused byearthquakes. One method of doing this is to provide a flexible, ratherthan rigid, means of connecting non-structural components to structuralcomponents of a structure such as a building.

It may also be desirable to provide flexible means of connectingstructural components to dampen or decrease the transmission ofvibrations during a severe event such as an earthquake. However, suchflexible connecting means can be impractical during construction ornormal conditions of service for a number of reasons. For instance,construction requires predictable, fixed tolerances which may not beachievable using flexible connectors. Also, a structure with excessiveflexibility may at least be perceived to be unsafe. Furthermore, theflexible connector may be a compression fixing but the flexibility ofthe connector may hinder fastening of the connector. For instance, in aconnector with a torsional flexibility, the flexibility will act asbiasing means during fastening which will bias the connector in anunfastening direction. It is desirable to provide a means of connectingstructural components which provides compressive rigidity during normalin service conditions and dynamic flexibility during excessive dynamicloading conditions.

The human body has a mechanism for resisting and reducing damage fromunexpected forces and this relies upon the elastic properties of thetendon. For example there are certain configurations of bones and jointswithin the skeletal frame that provide axial rigidity in normalcircumstances but also precipitate the tendons to stretch in response tonon-axial loads.

Compression fasteners or tension elements for resisting lateral loadsform part of many structural systems. However, to overcome existingdesign, engineering and building constraints and performancelimitations, it is desirable to create a means of mechanical anchor,with tendon like responsiveness, that uses passive embedded, tensionpotential and elastic deformation in the dynamic way proposed.

There are also a number of problems with existing technology relating tofacade systems for buildings. Current cladding systems, such as precastconcrete panels with decorative elements, are extremely heavy tomanoeuvre and align accurately. They can require extremely largemanufacturing premises as each panel has to be laid flat duringmanufacture. The panels can also take upwards of two weeks to curebefore they can be handled with specialist lifting equipment.

Timber or steel frame components, sheathing boards and cladding all varyin dimension and tolerances and have to be altered to create compatiblecomponents. Off-site construction methods rely on components beingtransported to site economically. This can be problematic due to theweight, size and structural integrity of these components.

Also, existing insulating brick cladding panels are not structural and,in the event of seismic activity, can become dislodged as they do notallow for the movement involved.

Lightweight construction techniques such as timber frame and metalsection rely on cladding systems to provide aesthetics to the structure.These cladding systems do not currently provide a homogonous ‘throughwall’ solution. Timber construction relies on the framework to beboarded with structural timber-based sheeting products such as plywoodwhich are costly, heavy, and can absorb moisture making themdimensionally or structurally unstable. Alternatively, cement basedparticle boards can be used but these are heavy and costly.

Current cladding methods typically rely solely on chemical fixing ofdecorative elements which can fail on site, especially if installationconditions are variable.

According to a first aspect of the present invention there is provided aload bearing member comprising:

-   -   a first rigid portion adapted to bear a load until the load        reaches a predetermined load and thereafter have a reduced or        substantially no load bearing capacity; and    -   a second flexible portion adapted to bear the load after the        predetermined load is reached,    -   wherein the first rigid portion and the second flexible portion        cooperate to bear the load such that the load bearing member is        enabled to transform from rigidly to flexibly bearing the load        when the predetermined load is reached.

The term “flexible” is intended to cover any means that allows thesecond portion to deflect in one or more directions under loading. Thisincludes but is not limited to: a property, such as an elasticity,viscoelasticity or plasticity, of a material forming the second portion;or a geometric configuration that promotes bending, buckling,stretching, compression or rotation of the second portion; or amechanical arrangement.

The first rigid portion may be adapted to fail at the predeterminedload. The first rigid portion may include a weakening feature adapted tofail at the predetermined load. Failure at the predetermined load may bedue to a material forming the first rigid portion reaching a failurevalue. The failure may be due to fracture or plastic collapse or elasticbuckling of the material. The weakening feature may be adapted torespond more to particular types of loading and less to other types ofloading.

The weakening feature may be provided at a predetermined axial location.A weakening feature may be provided at a plurality of predeterminedaxial locations.

Alternatively, the load bearing member may include switching means andload sensing means and the load bearing member is adapted to switch fromthe first rigid portion to the second flexible portion for bearing theload when the predetermined load is reached. The load bearing member maybe adapted to switch from the second flexible portion to the first rigidportion for bearing the load when the load falls below the predeterminedload.

The first and second portions may be configured to bear a load inparallel. The first rigid portion may be arranged to bear the majorityof the load prior to the predetermined load is reached.

The second flexible portion may be provided as an inner core of thestructural member and the first rigid portion may substantially surroundthe inner core.

The first rigid portion may be provided as a hollow tubular member. Thesecond flexible portion may be provided as an inner wire or the likeprovided within the tubular member. The second flexible portion may beprovided with anchor points at each end of the inner wire.

Alternatively, the second flexible portion may be formed by removingmaterial from a solid member to form a waist portion. The first rigidportion may be provided as a collar member provided around the waistportion.

The first rigid portion and second flexible portion may be provided asan insert for retrofitting to a conventional structural member.

The load bearing member may comprise a beam, column, bracket, hanger,strut, axle, cable, pipe, pipe joint, or the like.

Alternatively, the load bearing member may comprise a compressionfastener such as a bolt, nut, rawlplug screw, washer, nail, clamp or thelike.

The load bearing member may comprise a fastener and include a washermember. The washer member may comprise a resilient material, such asrubber. The washer member may include a recess or cavity adapted toallow displacement of the second flexible portion. The cavity maycontain a gas such as air. The washer may include an aperture having anentrance for the fastener and an exit spaced apart from the entrance andthe entrance may be oversized relative to the fastener.

The load bearing member may include a sleeve member. The sleeve membermay include a joint portion at a location corresponding to thepredetermined axial location. The joint portion may be flexible. Thejoint portion may comprise a concertina member. Alternatively, the jointportion may be rigid until the predetermined load is reached andthereafter flexible. The joint portion may be adapted to fail at thepredetermined load.

The load bearing member may include transformation indicating meansadapted to indicate when the load bearing member has transformed fromrigidly to flexibly bearing the load. The transformation indicatingmeans may comprise colour coding or movement of a flag member from afirst position to a second position.

A testing device may be provided for determining whether the loadbearing member has transformed from rigidly to flexibly bearing theload. The testing device may cooperate with the transformationindicating means. Alternatively, the testing device may be adapted toinvestigate the state of the first rigid portion.

The load bearing member may be formed from any suitable material, suchas steel, aluminium, plastic or composite. The first rigid portion maybe formed from a first material and the second flexible portion from asecond different material. The first material may be selected for itsfailure characteristics. The second material may be selected for itsflexibility and/or strength.

The compression fastener may be adapted for fastening a facade, such asa brick or stone slip system, or any other type of decorative or nondecorative element to a structure such as a building.

The load bearing member may form part of the facade of a building. Thefacade may comprise a plurality of facade elements, such as brick orstone slips, which are attached to a support which is fastened to anexterior surface of the building using a plurality of fasteners. One ormore of the fasteners may comprise the first rigid portion and thesecond flexible portion.

The support may be configured to cover a substantial portion of theexterior surface.

The facade may include a matrix material interposing the support and theexterior surface. The matrix material may comprise a first layer ofcompressible material, such as foam, and a second layer of rigidmaterial. The second layer may include a plurality of cavities. Thesecond layer may be a honeycomb material. According to a second aspectof the present invention there is provided a method of supporting a loadwithin a structure using a load bearing member, the method comprising:

-   -   providing the load bearing member with a first rigid portion        adapted to have a load bearing capacity until a predetermined        load is reached and thereafter have a reduced or substantially        no load bearing capacity; and    -   providing the load bearing member with a second flexible portion        adapted to bear the load after the predetermined load is        reached.

The method may include adapting the first rigid portion to fail at thepredetermined load. The method may include selecting a material formingthe first rigid portion which will reach a failure value at thepredetermined load. The method may include configuring the first rigidportion to fracture, plastically collapse or elastically buckle at thepredetermined load.

The method may include providing the second flexible portion as an innercore of the structural member and the first rigid portion assubstantially surrounding the inner core.

The method may include providing the first rigid portion as a hollowtubular member and the second flexible portion as an inner wire or thelike provided within the tubular member. The method may includeproviding anchor points at each end of the inner wire.

Alternatively, the method may include forming the second flexibleportion by removing material from a solid member to form a waist portionand providing the first rigid portion as a collar member around thewaist portion.

The method may include retrofitting the first rigid portion and secondflexible portion to a conventional structural member.

The method may comprise supporting a plurality of facade elementsprovided on the exterior surface of a building. The facade elements maybe attached to a support which is fastened to an exterior surface of thebuilding using a plurality of fasteners. One or more of the fastenersmay comprise the first rigid portion and the second flexible portion.

The method may include interposing a matrix material between the supportand the exterior surface. The matrix material may comprise a first layerof compressible material, such as foam, and a second layer of rigidmaterial. The second layer may include a plurality of cavities. Thesecond layer may be a honeycomb material.

According to a third aspect of the present invention there is provided afacade system which is installable on the exterior surface of astructure, the facade system comprising:

-   -   a plurality of facade elements;    -   a support for supporting the facade elements and which is        attachable to the exterior surface using a plurality of        fasteners; and    -   a matrix material interposing the facade elements and the        exterior surface, wherein the matrix material comprises a first        layer of compressible material and a second layer of rigid        material.

The first layer may comprise a foam material.

The second layer may include a plurality of cavities. The second layermay be a honeycomb material.

The matrix material may interpose the support. Alternatively, the matrixmaterial may be adapted to provide the support.

One or more of the fasteners may comprise a first rigid portion and asecond flexible portion.

The first rigid portion may be adapted to fail at the predeterminedload. Failure at the predetermined load may be due to a material formingthe first rigid portion reaching a failure value.

Embodiments of the present invention will now be described, by way ofexample only, with reference to the accompanying drawings in which:

FIG. 1 is a side view of a fastener according to a first embodiment ofthe invention;

FIG. 2 is a cross sectional side view of the fastener of FIG. 1;

FIG. 3 is a cross sectional end view of the fastener of FIG. 1;

FIG. 4 is a cross sectional side view of a fastener according to asecond embodiment of the invention;

FIG. 5 is a side view of the fastener of FIG. 1 fastening a panel to awall of a building; and

FIG. 6 is a perspective view showing a number of variations of washersthat can be used with a fastener according to the invention.

FIGS. 1 to 3 show a load bearing member which in this embodiment is inthe form of a bolt 10. The bolt 10 has a first rigid portion comprisinga shaft 12 having a hollow portion 14. The shaft 12 includes a weakeningfeature in the form of fracture lines 16 at a distance 100 from the head18 of the bolt 10. The bolt will be subject of various types of loadingsuch as tension, shear and torsion, and torque will be applied to fastenthe bolt 10. The number, depth and direction of the fracture lines 16are selected so that the shaft 12 will catastrophically fail at apredetermined load. Therefore, the shaft 12 is adapted to bear a loaduntil the load reaches a predetermined load and thereafter will have noload bearing capacity. Also, the direction of the fracture lines 16 canbe selected to promote failure from a particular type of loading. Forinstance, in FIG. 1, the fracture lines 16 are normal to thelongitudinal axis of the bolt 10. Therefore, tensile and shear loads aremore likely to cause fracture than, say, torsional loads. Such loads aremore commonly produced during the dynamic loading associated with wavepropagation and seismic movement from earthquakes. This feature alsominimises the likelihood of undesirable catastrophic failure duringfastening of the bolt 10.

A second flexible portion in the form of a connector wire 20 is providedwithin the hollow portion 14 between two anchor points. The wire isselected to sustain a load which exceeds the intended in service loadingdemands and therefore a greater load than the predetermined load.Therefore, like a performance enhancing tendon, the wire 20 will bearthe load after the predetermined load is reached.

The hollow portion 14 of the bolt 10 is particularly suitable forresisting bending loads since the material is offset from the centrelineof the shaft 12. The wire 20 will be flexible during bending as it ispositioned at the centreline. A wire has an elasticity which allows adegree of elongation during tensile loading. To increase the possibledisplacement in this direction, the wire 20 may be provided with someslackness.

It can be seen that the hollow portion 14 and the wire 20 are configuredto bear the load in parallel. However, the hollow portion 14 will bearthe majority of the load prior to the predetermined load being reached.

FIG. 4 shows an alternative embodiment of the load bearing member, stillin the form of a bolt 10 and like features are given like referencenumerals.

A waist portion 22 is formed by removing material from a convention boltshaft which effectively acts as the flexible wire of the firstembodiment due to its reduced diameter. A collar 24 is provided aroundthe waist portion 22 which is formed from a brittle material. Thebrittle material is selected to fail at the predetermined load andthereafter the waist portion 22 will bear all of the loading.

In an alternative embodiment, which can be based on the first or thesecond embodiments, the first rigid portion and second flexible portioncan be provided as an insert for retrofitting to a conventional bolt.

There are many other ways of forming the load bearing member. Theflexible portion could be cast in to the rigid portion. Or the flexibleportion could be mounted at the exterior or around the rigid portion,such as a spring member coiled around the flexible portion and having anend attached to the rigid portion on both sides of the fracture lines16.

FIG. 5 shows the bolt 10 of the first embodiment fastening a facadepanel 110 to a wall 112 of a building. The location of the fracturelines 16 is predetermined so that they are located at the interface ofthe panel 110 and wall 112. This is important as, if the fracture lines16 are located within the wall then the wall could restrict flexibility,whereas if the fracture lines 16 are located within the panel then thepanel could be damaged or vibrations could be propagated from the wallto the panel.

A range of bolts 10 of the invention can be provided with the fracturelines 16 at a variety of locations to correspond to different standardor non-standard thickness of panels or elements. For standard panels,the fracture lines 16 simply have to be located at a distance from thehead 18 which corresponds to the thickness of the panel being used. Fornon-standard panels, packer elements, such as washers or straps, can beprovided between the head 18 and the panel to ensure that the fracturelines 16 are located at the interface.

Post-installation adjustment means can be provided. In particular, thebolt 10 can be adjusted so that the fracture lines are at the interface.

In certain situations, more than one panel may be being fastened to thewall 112. The bolt 10 can be adapted to have fracture lines 16 at morethan one location along its shaft 12, with each location correspondingto an interface of the panels or of a panel and the wall 112. Such abolt 10 could also be useful for cavity walls.

During normal conditions, the bolt 10 acts as a conventional boltsupporting static loading from the weight of the panelling. The hollowportion 14 will support the majority of this static loading. During anearthquake, the wall 112, which is directly or indirectly rigidlyconnected to structural components at the ground, will vibrate whichwill exert dynamic loading on the bolt 10. When this dynamic loadingreaches the predetermined load, the hollow portion 14 will fracture andthe wire 20 will then take up the loading. The wire provides the dynamicflexibility and inherent strength required. Therefore, the panel 110will still be fastened to the building but in a more flexible mannerwhich accommodates relative displacement between the panel 110 and thewall 112.

The bolt 10 can be configured such that, after the hollow portion 14 hasfractured, a portion of the hollow portion 14 is sacrificed or released.The remaining portions can provide a failsafe retaining capability.

A washer may be provided which is formed from a resilient material suchas rubber. This increases the flexibility of the bolt 10 both before andafter the predetermined load has been reached. And by allowing a greaterrelative displacement, the washer can also increase the predeterminedload which may be desirable. The washer can comprise two rigid plateswhich sandwich a rubber material, with an aperture through the washerfor receiving the bolt 10. The rubber material allows relative lateraldisplacement of the two plates during dynamic loading. The aperture atthe outer plate (adjacent to the head 18) can be made to be oversizedrelative to the bolt outer diameter to accommodate pivoting of the bolt10 relative to the outer plate (the side walls of the aperture will notrestrain the bolt 10 from pivoting). Alternatively, the aperture at theinner plate can be oversized.

The washer can also include a recess or cavity to allow greaterdisplacement of the wire 20 after the predetermined load has beenreached. The recess provides a volume of space allowing unrestrainedmovement of the bolt 10 other than at the outer plate. The recess also,by removing material from the washer, allows greater deformation of thewasher caused by dynamic movement of the bolt 10. In the case of thewasher having a cavity, this cavity can be filled with a gas such asair. This arrangement does not interfere with dynamic movement of thebolt 10 but assists in the washer returning to its non-deformed state.

Examples of such washers are given in FIG. 6 which shows washers bothwith and without the recess. As shown in certain examples, the washercan be adapted for a single bolt or for many and can even be provided asa full panel. Also, the washer can be adapted to fit to a corner of thebuilding.

It is common, when fastening a fastener to a substrate, to use a sleeveinserted into the substrate for receiving the fastener. The sleeveprotects the fastener from corrosion. The load bearing member accordingto the invention can include a sleeve which has a joint portion at alocation corresponding to the predetermined axial location of thefracture lines 16. The joint portion can be flexible such as beingformed as a concertina member which allows bending, compression andelongation, or the joint portion can be rigid until failure at thepredetermined load and thereafter flexible. In an alternativeembodiment, the sleeve can be adapted to provide the second flexibleportion of the load bearing member.

The load bearing member can be provided with transformation indicatingmeans to indicate when the load bearing member has transformed fromrigidly to flexibly bearing the load. This may comprise colour coding inwhich the colour appears or changes when the load bearing member hastransformed. Or a flag member could be provided which changes from afirst position to a second position when the load bearing member hastransformed. Or a sensor may be embedded which detects thetransformation and sends a signal to a visual or auditory alarm device.The alarm device can be provided at the load bearing member or may beremote.

A testing device may be provided for determining whether the loadbearing member has transformed. The testing device may cooperate withthe transformation indicating means. Alternatively, the testing devicemay be adapted to investigate the state of the first rigid portion, suchas by testing the flexibility of the load bearing member.

While the foregoing description relates to a bolt, it can be appreciatedthat the invention can apply to any fastener such as a nut, screw,rawlplug, washer, nail, clamp or the like.

However, it should also be appreciated that the invention may relate toa structural component (a structural part of the building) such as abeam, column or bracket, or it may relate to an insert for such acomponent.

Considering again FIG. 5, the flexible connector is particularlysuitable for attaching a facade system to a building. To further inhibitdamage to the facade, the facade can include a matrix materialinterposing the support for facade elements (not shown) and the exteriorsurface. The matrix material can comprise a first layer of compressiblematerial, such as foam, and a second layer of rigid material.

The foam layer has a mesh layer either side bonded on to it using anadhesive. The foam layer allows greater relative displacement but isrelatively structurally weak. The second layer, being rigid, isstronger. The second layer can be a honeycomb material which includes anumber of cavities. These act to absorb vibrations and so limit thepropagation of vibrations to the facade elements.

The embodiment also increases the in-plane shear performance of thefacade and its attached elements by enhancing the ability to resistseismic shear forces. This ability to improve and maintain verticalresistance after sustaining significant in-plane shears is due to theembodiment capability to deliver a secure and an elastic response upondemand. Therefore a decrease or loss of in-plane shear strength andstiffness in the facade or (conceivable) out-of-plane structural failurecan to some extent be abridged by this embodiment.

FIG. 7 shows another embodiment of a façade system according to theinvention.

Fixings 30 are used to fix the façade system to a structural member ofthe building. These fixings 30 can be a load bearing member, such as thebolt 10, according to the first aspect of the invention.

Façade elements 32 are bonded, using an adhesive layer 34 to a meshlayer 36. The adhesive layer 34 provides pressure and/or chemical and/orheat bonding of the façade elements 32. The adhesive, in liquid form,expands under pressure within a moulding press to achieve homogonousbonding throughout. This layer 34 also prevents water absorption andprovides a thermal break between the external façade elements 32 and theinternal structure of the building.

The mesh layer 36 comprises a rigid or flexible material which isencapsulated within the adhesive layer 34. The mesh layer 36 can alsoprovide for spacing and/or support of the façade elements 32 during thebonding process. The mesh 36 can be flat or profiled for reinforcing theoverall panel. The mesh 36 incorporates alignment markers to facilitatethe alignment of the mesh relative to the mould casing and/or façadeelements 32. The mesh can be made up from a series of plates, strips oras one continuous sheet.

Connection between panels is provided by members 38 which can either beincorporated into the mesh material or provided as separate elementssuch as plates, strips, tabs or the like. The connection system locatesthe mesh 36 and fixing points. It can comprise locating members on theperimeter of the mesh 36. These members 38 can interlock the edges ofthe mesh or the whole panel. When mesh elements and/or whole panels arelocked together, a homogonous mesh across a defined section of thebuilding structure is created. Where two panels connect, the façadeelements 32 (which are pre-bonded together under pressure by theadhesive layer 34) are inserted between the locking interface. Thiscovers the join between panels and masks the fixings which are exposedat the locking interface. Each panel can have an exposed area measuringhalf the size of a façade element 32 so that, when the panels arebrought together, a full façade element can be inserted into the exposedarea.

Inserts 40 can be incorporated into the mesh material or can be providedas a separate element. The insert 40 locates the mesh 36 within themould and positions the mesh 36 relative to the fixing points which aredispersed between façade elements 32. The insert 40 spreads the load ofthe fixing preventing the head of the fixing from pulling through thesurface and damaging the adhesive layer 32.

A binding element 42 in the form of a sheet material is bonded to theadhesive layer 32 during the pressure bonding process. The bindingelement acts as a medium between the adhesive layer 32 and a secondadhesive layer 44. This medium facilitates a strong, keyed bond betweenthe two adhesive layers. The second adhesive layer 44 bonds the adhesivelayer 32 to a drainable/non drainable honeycomb board 46. By chemicallybonding these elements, a strong, rigid, light weight, homogonous panelis created.

The drainable/non drainable honeycomb board 46 can be made up from acombination of materials such as fibreglass, metals, magnesium oxideboard and the like. The boards 46 can be vented or unvented and caninhibit or allow the passage of moisture. The board 46 has the abilityto create a drainable cavity which is a standard requirement for manytypes of construction under current building regulations. As a result,the honeycomb board 46 bypasses the need for a separate cavity withinwall.

Steel or timber frames 48 are used to create a rigid, light weightstructure. The frame can use proprietary fixings or load bearing membersaccording to the first aspect of the invention.

The complete walling system can be mounted in such a way that they caneither be attached to the main sub-structure or isolated from the mainstructure and able to move independently under specific circumstancessuch as seismic shock. Isolation from the main structure compensates andprotects the overall cladding configuration from the effects of lovewaves and other forces. The frame sections are insulated on the internalside of the wall allowing for soft or rigid insulation to be used.

The facade of the invention provides a holistic solution, rather than anelemental solution, for the external or internal use of walling. Thecore of the system is created in specifically designed moulds which bond(under pressure) the façade elements 32 to a reinforcing mesh 36. Thiscreates a highly robust and lightweight component. This component isthen bonded to a drainable/non-drainable honeycomb board 46. At thisstage a rigid panel is created which can then be attached mechanicallyto frame members.

The system can be manufactured in flat panels and/or in corner panelswhich are used for external/internal building corners and reveals.

The panels are lightweight and strong and structurally stable enablingthem to be lifted and transported easily. Due to their light weight, thepanels can be aligned and fixed to the frame members with ease. Fullwall panels can be assembled quickly as pressure bonding and chemicalbonding processes take hours rather than weeks to cure.

The components of the panels are pre-matched to ensure that all fixings,structural members and façade elements align and interact in a modularfashion. Whole wall systems can be manufactured off-site enablingreduced build schedules with less dependency on weather conditions orwet trades. A complete, homogonous through wall solution can be achievedwith both external and internal wall finishes being applied ontostructural framework off-site.

The use of flexible fixings provides flexibility throughout thehomogonous structure which enables the decorative elements to remainisolated from any shock.

Honeycomb board technology combines moisture resistance, light weight,strength, stability and drainable/non-drainable options which create theopportunity to avoid heavy, costly, moisture absorbing sheetingmaterials. Authentic brick finishes can be achieved off-site and in afactory controlled environment. The panels provide accurate brickspacing over large areas with the security of chemical and mechanicalfixing.

Whilst specific embodiments of the present invention have been describedabove, it will be appreciated that departures from the describedembodiments may still fall within the scope of the present invention.

1. A load bearing member comprising: a first rigid portion adapted tobear a load until the load reaches a predetermined load and thereafterhave a reduced or substantially no load bearing capacity; and a secondflexible portion adapted to bear the load after the predetermined loadis reached, wherein the first rigid portion and the second flexibleportion cooperate to bear the load such that the load bearing member isenabled to transform from rigidly to flexibly bearing the load when thepredetermined load is reached.
 2. A load bearing member as claimed inclaim 1, wherein the first rigid portion is adapted to fail at thepredetermined load.
 3. A load bearing member as claimed in claim 2,wherein the first rigid portion includes a weakening feature adapted tofail at the predetermined load.
 4. A load bearing member as claimed inclaim 1, wherein failure at the predetermined load is due to a materialforming the first rigid portion reaching a failure value.
 5. A loadbearing member as claimed in claim 3, wherein the weakening feature isadapted to respond more to at least one particular type of loading andless to other types of loading.
 6. A load bearing member as claimed inclaim 3, wherein the weakening feature is provided at a predeterminedaxial location.
 7. A load bearing member as claimed in claim 6, whereina weakening feature is provided at a plurality of predetermined axiallocations.
 8. A load bearing member as claimed in claim 1, includingswitching means and load sensing means, and wherein the load bearingmember is adapted to switch from the first rigid portion to the secondflexible portion for bearing the load when the predetermined load isreached.
 9. A load bearing member as claimed in claim 1, wherein thefirst and second portions are configured to bear a load in parallel. 10.A load bearing member as claimed in claim 1, wherein the first rigidportion is arranged to bear the majority of the load prior to thepredetermined load is reached.
 11. A load bearing member as claimed inclaim 1, wherein the second flexible portion is provided as an innercore of the load bearing member and the first rigid portionsubstantially surrounds the inner core.
 12. A load bearing member asclaimed in claim 11, wherein the first rigid portion is provided as ahollow tubular member and the second flexible portion is provided as awire member provided within the tubular member.
 13. A load bearingmember as claimed in claim 1, wherein the second flexible portion isformed by removing material from a solid member to form a waist portion.14. A load bearing member as claimed in claim 13, wherein the firstrigid portion is provided as a collar member provided around the waistportion.
 15. A load bearing member as claimed in claim 1, wherein thefirst rigid portion and second flexible portion are provided as aninsert for retrofitting to a conventional load bearing member.
 16. Aload bearing member as claimed in claim 1, comprising at least one of abeam, column, bracket, hanger, strut, axle, cable, pipe, and pipe joint.17. A load bearing member as claimed in claim 1 comprising a compressionfastener.
 18. A load bearing member as claimed in claim 17, including awasher member comprising a resilient material.
 19. A load bearing memberas claimed in claim 18, wherein the washer member includes a recess orcavity adapted to allow displacement of the second flexible portion. 20.A load bearing member as claimed in claim 19, wherein the cavitycontains a gas.
 21. A load bearing member as claimed in claim 18,wherein the washer includes an aperture having an entrance for thefastener and an exit spaced apart from the entrance, and wherein theentrance is oversized relative to the fastener.
 22. A load bearingmember as claimed in claim 17, including a sleeve member.
 23. A loadbearing member as claimed in claim 22, wherein the sleeve memberincludes a joint portion at a location corresponding to thepredetermined axial location.
 24. A load bearing member as claimed inclaim 23, wherein the joint portion is flexible.
 25. A load bearingmember as claimed in claim 1, including transformation indicating meansadapted to indicate when the load bearing member has transformed fromrigidly to flexibly bearing the load.
 26. A load bearing member asclaimed in claim 1, wherein the first rigid portion is formed from afirst material and the second flexible portion is formed from a seconddifferent material.
 27. A load bearing member as claimed in claim 1,wherein the load bearing member is adapted for fastening a facade to abuilding.
 28. A method of supporting a load within a structure using aload bearing member, the method comprising: providing the load bearingmember with a first rigid portion adapted to have a load bearingcapacity until a predetermined load is reached and thereafter have areduced or substantially no load bearing capacity; and providing theload bearing member with a second flexible portion adapted to bear theload after the predetermined load is reached.
 29. A method as claimed inclaim 28, including adapting the first rigid portion to fail at thepredetermined load.
 30. A method as claimed in claim 29, includingselecting a material forming the first rigid portion which will reach afailure value at the predetermined load.
 31. A method as claimed inclaim 28, including providing the first rigid portion as a hollowtubular member and the second flexible portion as an inner wire providedwithin the tubular member.
 32. A method as claimed in claim 28,including forming the second flexible portion by removing material froma solid member to form a waist portion, and providing the first rigidportion as a collar member around the waist portion.
 33. A method asclaimed in claim 28, wherein the load bearing member comprises afastener.
 34. A method as claimed in claim 33, including supporting,using a support, a plurality of facade elements provided on the exteriorsurface of a building, and fastening the support to the exterior surfaceusing at least one load bearing member. 35-45. (canceled)